As a bottle making machine generally called “I.S. machine,” there is a machine having a plurality of divided sections, and bottles are formed one after another by molds provided in each section. The molds provided in each section include a blank mold for receiving a molten glass lump called “gob” therein to form a parison as an intermediate form, and a blow mold for receiving the parison transferred from the blank mold therein to finish it into a bottle in the final form. Note that in the following description, there are cases where a “blank mold” or a “blow mold” is simply referred to as a “mold,” and a “blank mold” and a “blow mold” are collectively referred to as “molds.”
The bottles manufactured one after another in each section are sent out onto a conveyor on a bottle transport path and transported to a final packing process through an annealing process and an inspection process. In the inspection process, bottles are inspected by an inspection machine or visually to determine whether the bottles have defects.
Each section is provided with cooling devices for applying cooling air respectively to the blank mold and the blow mold to control the temperatures of the molds (see Patent Literature 1, for example). If the temperature of the blank mold or the blow mold is higher than its target value, an air volume of the cooling air is increased to facilitate heat dissipation from the mold, thereby lowering the temperature of the mold. If the temperature of the blank mold or the blow mold is lower than its target value, an air volume of the cooling air is decreased to suppress heat dissipation from the mold, thereby increasing the temperature of the mold. Bottles formed by a mold with an inappropriate temperature differ from non-defective products in their forms such as bulges, and have defects such as cracks or wrinkles thereon.
FIG. 17 shows a configuration of a blank-mold cooling device X provided in each section, and FIG. 18 shows a configuration of a blow-mold cooling device Y provided in each section. Each section is provided with two blank molds 1A and 1B and two blow molds 2A and 2B. Each of the blank molds 1A and 1B is composed of a pair of split molds 11 and 12, and each of the blow molds 2A and 2B is also composed of a pair of split molds (not shown in the drawing).
A pair of cooling mechanisms 3L and 3R of a system in which cooling air is blown to both of the blank molds 1A and 1B from opposing positions outside the blank molds 1A and 1B to cool the surfaces of the blank molds 1A and 1B are provided for the two blank molds 1A and 1B shown in FIG. 17. Also, cooling mechanisms 4A and 4B of a system in which cooling air is introduced into a plurality of through holes running vertically through the blow molds 2A and 2B to cool the blow molds 2A and 2B from inside thereof are provided for the blow molds 2A and 2B shown in FIG. 18. The blank molds 1A and 1B and the blow molds 2A and 2B are controlled so that the temperatures of the molds become a target value by the application of cooling air by the respective cooling mechanisms 3L, 3R, 4A, and 4B.
A temperature sensor 5 for detecting the temperature of a mold is provided in one split mold 11 in one blank mold 1A by embedding or the like. The temperature sensor 5 outputs a temperature detection signal having a magnitude proportional to the temperature of the mold. This temperature detection signal is inputted to a blank-mold temperature indicator 7 together with temperature detection signals from other blank-mold temperature sensors, and temperatures of the blank molds in all of the sections are individually displayed on a number indicator panel not shown in the drawing.
A similar temperature sensor 6 is provided in one split mold in one blow mold 2A. A temperature detection signal outputted from the temperature sensor 6 is inputted to a blow-mold temperature indicator 8 together with temperature detection signals from other blow-mold temperature sensors, and temperatures of the blow molds in all of the sections are individually displayed on a number indicator panel not shown in the drawing.
The temperature detection signals of the blank mold 1A and the blow mold 2A in each section, which are inputted to the blank-mold temperature indicator 7 and the blow-mold temperature indicator 8, are A/D converted, and each temperature data is inputted to a temperature control device 9. The temperature control device 9 generates and outputs switching control signals for controlling opening and closing operations of solenoid valves 31 and 41 of the valve mechanisms 30 and 40 based on each temperature data, and each adjusts air volumes of cooling air sent to the cooling mechanisms 3L, 3R, 4A, and 4B, for example, by open time of the valves, i.e., cooling time.